LB9 CNC lathe- No display from Monitor and VACIII unit

[Motufaga]

Hi,

I have been trying to repair this machine (CNC lathe LB9 OSP500L-G)and hope someone can help me with these:

1) There is no display on the monitor when the machine's main breaker is
switched ON
The Control ON/Reset switch when pressed lights up with the NC status lamps and then all trips OFF. On tripping OFF, the OPUS 500 unit(CPU rack) shows 3 lamps on ON state; i) under voltage ii) +24V iii)+12V

If CPU power supply module is removed from its "connector slot" and the main breaker switched ON, the Control ON/Reset switch lamp lights up when pressed.No alarm lamps light up on the CPU rack but +5VDC,+12VDC and +24VDC are measured on the power supply unit with the multimeter.


2) None of LED's on the VAC III spindle drive unit are ON.
The voltages measured between the inputs of 3P lines to the spindle drive unit are 200V AC.The labeling on the 3 phase lines are: R2B,S2B and T2B.
The output lines to VAC motor (labelled U1,V1 and W1) measured zero between phases and 3.5V AC when measured to ground.

On the spindle drive Control PCB, CN7 connector pins 1 and 3 measured 7.5V AC and connector pins 2 and 3 measured zero volts .As the measured voltages are not 19V AC the manual states to replace power supply unit.
I have not found this power supply unit yet so I have decided to post this thread for feedback. Im a fitter machinist with CNC programing and machining experience and studying mechatronics.
Please any help on troubleshooting the above mentioned problems will be greatly appreciated. Thank you

[fordav11]

the 'under voltage' lamp suggests a power supply problem as you have found when you measured it and got 7.5V where there should be 19V.
so you need to find the power supply that is the source of the 19V and check it / repair it / replace it.
Power supplies are pretty easy to repair with some basic electronics knowledge and a little experience.
It'll be expensive to buy a new one (if you can find one) but you should try getting it repaired at a TV repair shop or a similar place.

[Motufaga]

Thank you fordav11.
After removing power supply board (VAC III unit with 50 screws on it) I found the transformer, magnetic contactor ,huge capacitor,transistors etc. behind the board.I discovered that almost all the screws represent test points on the power board so I fitted them back,switched on the main breaker and tested the board.
The inputs to the transformer were the same as the outputs (200V AC between the 3 phases or 115V between a line and ground).

The outputs from the transformer are connected to the magnetic contactor. There are no output voltages from the contactor and the two points for relay circuits of the contactor also measured 115V AC to ground.

Please if some one can help me with the what the output voltage from transformer be for this VAC III spindle drive unit?

[Motufaga]

Ive found that the transformer I mentioned in my last thread is not a transformer but a choke coil.

My eagerness to learn this electrical/electronics troubleshooting is making me feel stupid. My apologies.

I would like to say thanks to diegojulio for the VAC III maintenance manual
Im going through it and looking at my last thread the voltage measured between the two contact points of the relay for magnetic contactor was zero
any one of these points to ground =115V AC
The circuit for the relay for the magnetic contactor switch seems to be the problem

Ill post again when sort fix this problem

[Algirdas]

1. Do You have electric diagram of the machine?
2. Did You checked the +24V and, if it is there -24V ?
3. Are You trying to fix spindle drive unit? It looks, the control doesn't powers up, so Spindle drive is not the first to fix ...

[Motufaga]

Thanks Algirdas, with my little knowledge on electrical/electronics please guide me.

1. Do You have electric diagram of the machine?
No I do not have.

2. Did You checked the +24V and, if it is there -24V ?
Please help me on this one?

Ive checked -24VDC on a power supply - maybe for servo board???
Also measured +24V DC on (CPU power supply-rack insert type)

If +-24V is not from above but from VAC III spindle drive unit then please help me locate it?

3. Are You trying to fix spindle drive unit? It looks, the control doesn't powers up, so Spindle drive is not the first to fix ...


yes i was looking to remove magnetic contactor switch to find out why its not relaying from the input to its output.

Please point me in the right direction if not spindle drive?

Ive just measured CN8 (is it connector 8 ?) between pins 3 and 4 and its about 287V DC . VAC III manual says if not 300V DC then no power is going to Control PCB.

[Algirdas]

Let's start from the beginning:
1. no electric diagram.
no comment. nothing to comment. I would strive to get the one whatever costs. Okuma dealer must be able to provide, I believe.
2. +24V and -24V must be present on power supply block. It's in the CPU rack, most likely.
if You have +24V on Emergency stop terminals, it means, that control is powered up. If You have ±24V somewhere else, it means, control is ready to be powered up. Roughly saying ...
if control is powered up, You must see indication on OP. All indicators are on for a while on POST, to be sure they work.
3. i was looking to remove magnetic contactor switch to find out why its not relaying from the input to its output
please explain. what is not relaying from input to output?
4. Is there a reason to dig inside the drive unit?
can You switch on: - the machine; - the OSP?

[Motufaga]

3. i was looking to remove magnetic contactor switch to find out why its not relaying from the input to its output
please explain. what is not relaying from input to output?

Ok I was sick and now im back. ive drawn a diagram attached
There are voltages from the SDU input terminal to the magnetic (switch), but there are no output voltages from the magnetic switch to the three transistors.

4. Is there a reason to dig inside the drive unit?
can You switch on: - the machine; - the OSP?

Yes can switch On but the machine is not booting up nor display from monitor.
I was looking for the SDU power supply(stepdown,rectifier)...?? not sure...that is if DC voltage not from CPU or other power supplies.

1. no electric diagram.
no comment. nothing to comment. I would strive to get the one whatever costs. Okuma dealer must be able to provide, I believe.

Ive emailed Okuma dealer after I read your comment and with all that ive read about Okuma, wasnt raising my hopes but i received the wiring diagram today,great.Thanks, Im trying to understand the Japanese/English on it ha ha .....ill post the above anyway....

[Algirdas]

but there are no output voltages from the magnetic switch to the three transistors
Did You applied control voltage on contactor coil? No. Right, don't do that. Contactor is not on until is not commanded to. That's right
but the machine is not booting up nor display from monitor
this is a start position to diagnose: power supply first[/COLOR]
i received the wiring diagram today,great
Lucky You. Now You can handle where control voltage is missing and why.

[Motufaga]

Please help
Attached is the control Power Supply diagram.Ladder diagram?

Cant figure out the control voltage between +AL and -AL.?
zero voltage was measured between +-AL.
Is there a problem with this power supply?

[Algirdas]

the diagram looks familiar :-) what it means:
if voltage between AC1 and AC2 is about ~200V
and
there is no short circuit on +V -V terminals
and
P.S.C. unit is healthy
and
Control line "54N" is alive (+24V, I guess)
then
CB2 (Control Button #2 ?) is ready to switch on EC control voltage.
~~~~~~~~~
if line "56N" is alive (+24V, I guess)
EC control voltage can be switched on
~~~~~~~~~
+AL_-AL can be spikes (pulse). Measuring as constant voltage maybe wrong. check it

[Motufaga]

Thanks again Algirdas

After some testing there is DC 24V across 54N and 56N and also across +V and -V so there's no problem with the control power supply.

Testing the CPU power supply there are DC +5V, +12V, +24V, ISO+24V on its test terminals when powered ON and not connected to CPU rack

When connected to CPU rack and powered ON, none of voltages appeared(measured) on test terminals. Power supply alarm indicating lamps on CPU rack light up for under voltage, +24V and +12V.

From the manual these alarms indicate abnormality in the power supply or in input or output parts.

Please help me from here
From the above tests there don't seem to be a problem with power supply?

assuming the problem to be output from power supply to bubble memory(bubble memory require DC +24V and where loading is done) I cant tell if my system is loading or not because there is no display on control panel
How can I test the bubble card or CRP Board -II D which interfaces Control panel?
Or am I missing something ???????

another glitch!!;
Is it ladder diagram on control power supply diagram attached last thread?

Ive done PLC programing and interfacing but I still cant find what some of the symbols represent on the wiring diagrams?
i) two arrow heads ( PS diagram)
ii) line with circle and labelled pt (PS diagram)
iii) switch (normally open contact) with a number written to the left and right of it. what the numbers indicate?
iv) capacitor symbol or something else?( across +AL and -AL ---PS diagram)

Any help, contribution on the above will be greatly appreciated.
Thank you